A light emitting diode (LED) is capable of expressing almost all colors of nature using red, green, blue (RGB) lights. Furthermore, since the LED is environment-friendly, power saving, and semi-permanent, the LED is being widely used for lighting implementing various colors.
Conventionally, a digital multiplex (DMX) control method is generally used as an LED lighting control method.
The DMX, abbreviated from DMX512, transmits data of 250,000 bits (250 kbps) per second, using RS-485 that enables communication with two wires, and provides 512 channels per data link.
According to a conventional LED lighting device, a DMX controller generating a DMX control signal and a plurality of LED lighting devices are interconnected by the Daisy chain method.
The DMX controller transmits 512 consecutive packets to the LED lighting device. Here, according to DMX communication standard, one packet includes 1 bit as a start bit, 8 bits as data bits, and 2 bits as stop bits.
The LED lighting devices each have a unique address and thereby receive a data code of a corresponding packet and control lighting using the data code.
Since DMX data includes 8 bits, brightness of an LED may be adjusted by totally 256 (from 0 to 256) levels. When an RGB LED is used, totally 16,777,215 (2563-1) colors may be implemented.
However, the conventional LED lighting control method is insufficient for a harbor LED lighting device which requires high reliability, high stability, and high output.